William Tinzaara, Associate Scientist, based in our Uganda office, speaks about the work Bioversity International is carrying out with partners in East and Central Africa on banana pests and diseases - in particular, on the management of Banana Xanthomonas Wilt, a devastating bacterial disease which can wipe out entire yields of bananas.
Q: What is your role at Bioversity International?
A: I am an associate scientist based in Uganda, conducting research on banana pests and diseases in East and Central Africa, more specifically on the management of Banana Xanthomonas Wilt (BXW).
Bananas are a very important crop in Uganda, my home country, where domestic per capita consumption is estimated between 220-460Kg – the highest in the world. My family are subsistence farmers, so I grew up gaining first-hand experience and knowledge about the opportunities and challenges of smallholder farming, as well as understanding just how devastating banana pests and diseases can be to farmers’ livelihoods. I wanted to help find solutions.
Q: Can you explain more the challenges banana producers in the region are facing from pest and disease outbreaks
A: Banana disease, specifically the bacterial banana disease Xanthomonas wilt (BXW), is the major challenge. There are also outbreaks of Fusarium wilt, a fungal disease, and attacks from banana pests, such as weevils and nematodes. BXW is the main one and once it is in a field, if it is not managed properly, it can completely destroy the entire yield. Bananas are so important to us here in Uganda in terms of livelihoods and food security that losing an entire yield is devastating. But there are ways to manage outbreaks. This has been the focus of our research across the East African lakes region, working with partners and the farmers themselves, to find the best ways to do this.
Q; How did Bioversity International get involved in this research?
A: Bioversity International has a long history in banana research. We manage the largest banana collection in the world, through the International Transit Centre which is located in Belgium, and have worked for many years, and with many partners, around the world, on banana-related research, including pest and disease management. So in this case, we were able to talk to colleagues and partners in the Philippines, where similar diseases have broken out, and find out what worked and didn’t work there. We have also worked for a long time in this region, and so have many research and development partners including the National Agricultural Research Systems who understand our expertise in this area, so reached out to us to help.
Q: So what are some of the ways to manage BXW outbreaks?
A: As BXW is a bacterial disease, it can quickly pass from one banana plant to another, especially through the flowers on the male bud. The flowers attract the bees and in the process of the bees moving from one male bud to another, they can transmit the disease. So a simple but effective method is to simply remove the male bud but the way you do this is also important. Farmers traditionally remove the male buds using knives, which can also spread the disease from plant to plant. Using a forked stick instead of a knife avoids the problem, as you can break off the male bud without coming into contact with the rest of the plant. Of course, you also need to clean your tools properly for example by using a disinfectant, or passing the tools over fire.
Another really important management practice is to remove any diseased plants immediately. Originally in some countries in the East and Central Africa region, and particularly in Uganda, the recommendation and practice was that once a diseased plant was spotted, to remove all the plants in a plot, not just those that were infected. Now we advise removing just the diseased plant, you can leave the rest. This is really good news for the farmer who is dependent on his crop for food and income.
In parts of Uganda now, if a farmer has a diseased plant and it is not removed within 24 hours, he or she can face a fine, or even prison in some cases! Even in some areas where there are no bylaws but there is awareness of how to manage BXW, community pressure is ensuring quick action from farmers in removing diseased plants. And we are seeing the results – disease incidence is down from 80-90% to 0-10% disease incidence.
Q: Are there differences in the training given to manage the disease in the different project sites where Bioversity International is working?
A: Yes. Part of our research objective was to test management practices in different cropping systems. Even within Uganda, where we have two sites, we are seeing a difference. In our central Uganda site, in Kiboga, they mainly grow Kayinja bananas. Here we have found that the main cause of disease transmission is by insects. In our western Uganda site, in Bushenyi, you mostly find East African Highland bananas. Here we have found that the main cause of transmission is by tools. So this affects where you focus training. What we have also found is that when bananas are grown for largely commercial purposes, as in Bushenyi, farmers pay much more attention to managing the disease and so you see much better results than when they are grown just for home consumption. We find the same thing in Kenya, where banana production is on a very small scale, and it is not grown specifically for the markets. In this case, managing the disease is not so important to them. So in these cases you need to ensure that training focuses on why it matters in terms of preventing its spread to other farms.
Q: What are some important lessons learned during this research?
A: The main lesson is that it is really important to collaborate with the farmers on ways to manage the disease. We had tested the different practices on our research station before going out to the farms, to see what really worked well. But we found after sharing these practices with the farmers, we were not seeing much change. We thought initially that the farmers were simply choosing not to adopt the new ways of working, but on closer examination, we found that there were complex reasons for this, for example, that the farmers did not really understand why the suggested new practices worked, or what the disease looked like.
So we developed a much more collaborative approach, through an initiative called Learning, Experimentation, Approaches for Farmers (LEAFF), by actually going to the farms and working/doing experiments with the farmers. We were literally showing them how the disease moves so they could understand better, and this really improved adoption rates.
We would also say that successful disease management cannot be achieved by a single farmer. As a result of our efforts, the farmers have organized themselves into groups, and are now spreading control messages to non-group members. They not only share information through meetings and by using awareness materials we have provided for them to use, but they offer practical help, for example, if there is a farmer not able to remove the male buds, they will go and help them.
And the scope has expanded now through this initiative to include passing information about any new disease outbreaks to information on weather, markets, and so on. We are still researching in more depth the epidemiology of the disease, so these networks give us an effective way of continuing to update information directly to farmers, and also monitor the situation on the ground. The great news is that this approach can work for any crop, not just bananas, so we are looking more at that now.
This research is carried out in partnership with the National Agricultural Research Systems (NARS) of participating countries in East and Central Africa, It is delivered through Bioversity International’s Initiative on Productive and Resilient Farms, Forests and Landscapes, and as part of the CGIAR Research Program on Roots, Tubers and Bananas.
Top: Bioversity International associate scientist William Tinzaara discusses BXW disease management with farmer Enid Tumusilime, Uganda.
Middle 1: Banana plant affected by Xanthomonas Wilt (BXW), Uganda.
Middle 2: William Tinzaara visits one of the project sites, Uganda
Bottom: Taking bananas to market, Uganda
Credit for all photos: Bioversity International/N. Capozio